Csillagászat (benne az asztrofizika és az űrtudomány)
We present an analysis of TRAPPIST-1 like ultracool dwarfs with TESS full-frame image
photometry from the first two years of the primary mission. We constructed a volume-limited
sample up to 50 pc, consisting of stars in the vicinity of TRAPPIST-1 on the Gaia
color-magnitude diagram. We searched for flares and rotational modulation on the light
curves of 248 stars. We determined rotational periods for 42 stars, and estimated
the ages of 88 stars using kinematic information. A weak correlation between rotational
period and age is observed. The composite flare frequency distribution shows a power-law
index similar to TRAPPIST-1, and it is extended to higher energies. The results imply
that while superflares can be expected every few decades, the flare rate of such stars
is insufficient to fully destroy the possible ozone layer of orbiting planets.
